A wind turbine is a device that produces electricity by converting wind energy into mechanical energy and comes into the spotlight as a clean energy source for reducing a greenhouse gas. A conventional wind turbine includes a tower, a nacelle mounted on an upper part of the tower, and a rotor connected to the nacelle and having a plurality of blades.
In the wind turbine, periodic maintenance, such as cleaning, inspection, and deicing (to remove ice formed on a blade), is required even after installation so as to prevent a trouble or an accident and to improve operating efficiency. However, since the wind turbine is a large structure having a height of the tower of about 100 meters and a length of the blade of 40 to 70 meters or more, there are many difficulties in performing maintenance. In particular, since the blade is placed at a high altitude, a working environment is poor and dangerous, as a worker needs to stay in the midair for maintenance.
Since a maintenance condition of the blade is poor in this way, a device that is capable of performing maintenance without the worker's direct access to the blade has been suggested.
Japanese Patent Laid-open Publication No. 2002-115646 discloses a cleaning device that performs cleaning of a leading edge while moving along the leading edge of a blade. The device is equipped with a brush that moves along the leading edge of the blade and a driving instrument installed in the blade so that the brush can be moved, and including a motor, a gear, and a car wheel.
However, since, in the device, the driving instrument needs to be installed in the blade, a movement space of the driving instrument needs to be formed within the blade. Also, since slits need to be formed in the leading edge of the blade so as to connect the driving instrument inside the blade and the brush disposed at an outer side of the leading edge, rigidity of the blade may be degraded. A cleaning area is limited to the leading edge of the blade, and it is difficult to remove ice formed on the leading edge of the blade.
U.S. Patent Application Publication No. 2010/0132137 discloses a device that is capable of performing inspection and cleaning of a blade while travelling along an outer side of a leading edge of the blade. The device is equipped with a travelling body having a plurality of wheels for travelling along the leading edge, a driving unit for rotating the plurality of wheels, units for cleaning and inspection, and wing parts that extend to both lower sides of the travelling body so as to travel along the leading edge while keeping balance.
However, since the device keeps balance only by the wing parts that extend to both sides of the travelling body, it is difficult for the travelling body to stably travel along the leading edge. Areas to be cleaned and inspected are limited to the leading edge of the blade.